1. Field of the Invention
The present invention relates to a switch for vehicles, which is used for controlling the turn-on/off of a stop lamp when operating a brake pedal of a vehicle.
2. Description of the Related Art
Recently, a pressing-operation-type switch for vehicles is frequently used for controlling a stop lamp in accordance with the operation of a brake pedal. Specifically, the switch for vehicles turns on the stop lamp when the brake pedal is stepped on, and turns off the stop lamp when the brake pedal is not stepped on.
Such a conventional switch for vehicles will be described with reference to FIGS. 4 and 5.
FIG. 4 is a cross-sectional view of a conventional switch for vehicles. In FIG. 4, case 1 is formed in a box shape of which the top surface is opened and is formed of insulating resin. Operating body 2 is housed in case 1 so as to vertically move. Further, operating body 2 has magnet 3 mounted on a lower left side surface thereof.
A plurality of terminals 4 are formed of conductive metal. Wiring substrate 5 has a plurality of wiring patterns (not shown) formed on the right and left surfaces thereof. Wiring substrate 5 is disposed at the left side wall of case 1, and the upper ends of terminals 4 are connected to the wiring patterns of wiring substrate 5 through soldering or the like. Further, the lower ends of terminals 4 project downward from the bottom surface of case 1.
Wiring substrate 5 has detection device 6 such as a hall element and switching device 7 such as a power transistor formed on one surface thereof facing magnet 3. Further, control device 8 composed of an operational amplifier and a plurality of fixed resistors is formed on the surface of wiring substrate 5. Detection device 6 and switching device 7 are connected to control device 8.
Cover 10 formed of insulating resin covers the opening portion of the top surface of case 1. Further, coil-shaped return spring 9 is mounted in a state where it is bent between the lower surface of operating body 2 and the bottom surface of case 1. Return spring 9 biases operating body 2 upward, and the upper end of operating shaft 2A of operating body 2 projects upward from hollow cylindrical portion 10A formed in the center of the top surface of cover 10.
Movable contact 11 is formed of a conductive metal thin plate such as copper alloy. A plurality of fixed contacts 12 formed of copper alloy are planted into the right inner side wall of case 1. Further, the upper end of movable contact 11 is mounted and fixed to a lower right side surface of operating body 2, and the lower end of movable contact 11, which is set to be bent, is elastically contacted with the right inner side wall of case 1.
FIG. 5 is a side view of essential parts of a brake pedal using the conventional switch for vehicles. In FIG. 5, conventional switch 13 for vehicles constructed in the above-described manner is mounted in front of brake pedal 14 of a vehicle in a state where operating shaft 2A of operating body 2 is pressed by arm 14A. Further, the plurality of terminals 4 projecting from the bottom surface of case 1 are connected to a stop lamp, an ignition switch, a battery and so on through connector 15 and lead wires. Further, the lower ends of fixed contacts 12 projecting from the bottom surface of case 1 are connected to electronic circuits (not shown) of the vehicle.
In a state where brake pedal 14 is not stepped on, operating shaft 2A of operating body 2 is pressed downward while bending return spring 9, and magnet 3 mounted on the left side surface of operating body 2 is moved downward. Then, the center of detection device 6 disposed to face the center of magnet 3 is significantly separated from each other, and the magnetism of magnet 3 which is detected by detection device 6 decreases.
Control device 8 connected to detection device 6 controls switching device 7 based on the magnitude of the magnetism (magnetic flux density) detected by detection device 6. That is, when the magnetic flux density is equal to or more than a predetermined value, control device 8 switches switching device 7 into a close state. When the magnetic flux density is less than the predetermined value, control device 8 switches switching device 7 into an open state. Accordingly, in a state where operating body 2 is pressed, switching device 7 is set in the open state, and the stop lamp is turned off.
In a state where operating shaft 2A is pressed, movable contact 11 mounted on the right side surface of operating body 2 is also moved downward. Further, the lower end of movable contact 11 is elastically contacted with fixed contacts 12 such that fixed contacts 12 are electrically connected through movable contact 11. Accordingly, various functions controlled by the electronic circuits of the vehicle are operated. For example, a so-called auto-cruise device which constantly maintains the travel speed of the vehicle regardless of whether an accelerator pedal is stepped on or not is operated.
When brake pedal 14 is stepped on, arm 14A is separated from operating shaft 2A such that the pressing force is canceled. Therefore, as shown in FIG. 5, operating body 2 is moved upward by the elastic restoring force of return spring 9. Then, magnet 3 mounted on the left side surface of operating body 2 is also moved upward in such a manner that magnet 3 and detection device 6 face each other. Accordingly, the magnetism of magnet 3 which is detected by detection device 6 increases. Then, control device 8 switches switching device 7 into the close state, and the stop lamp is turned on.
Simultaneously, movable contact 11 mounted on operating body 2 is slid upward while being elastically contacted, and the plurality of fixed contacts 12 are electrically disconnected. Therefore, the auto-cruise control of the vehicle is stopped.
As such, operating body 2 of switch 13 for vehicles is vertically moved by the operation of brake pedal 14, and the turn-on/off of the stop lamp is controlled by detection device 6 and magnet 3 mounted on the left side surface of operating body 2 such that the operation and stoppage of the auto-cruise device is controlled by movable contact 11 on the right side surface and fixed contacts 12. As the related art document related to the invention of the present application, Japanese Patent Unexamined Publication No. 2006-92777 is known.
In the conventional switch for vehicles, however, since the turn-on/off of the stop lamp is controlled by magnet 3 and detection device 6 and the operation and stoppage of the auto-cruise device are controlled by movable contact 11 and fixed contacts 12, the number of used components increases, and the construction of the switch becomes so complex that assembling takes a lot of time.